(1) Field of the Invention
The present invention relates generally to package sorting conveyors and, more particularly, to a conveyor system having a conveying track, a transition zone funnel for receiving a package from the conveying track, selectively positionable between at least a first and second position, and a secondary chute downstream from the transition zone funnel having at least two definable discharge paths.
(2) Description of the Prior Art
Conveyor systems having a number of individual carrying carts have been used for many years to carry and sort packages such as shoes and apparel or other items such as mail. Conventional tilt tray sorters discharge their goods onto individual chutes located near each packer. For example, U.S. Pat. No. 5,054,601 to Sjogren et al. discloses a package sorting conveyor comprised of a train of tilt tray carriers coupled in tandem to form a continuous loop. Each carrier includes a pivotally mounted tilt tray normally maintained in an upright position. The carriers are moved around the loop by a series of motors spaced around the loop. Branching out from the loop are out-feed positions for receiving packages from the carriers. When a particular carrier holding a particular package to be sorted reaches a selected out-feed position, an actuator tilts the tray to dump the package into a transition zone funnel or other package-receiving device.
Another example of a similar package sorting conveyor is disclosed in International PCT Application No. PCT/DK90/00047 of Kosan Crisplant A/S.
One significant disadvantage of most conventionally designed package sorting conveyors is that the conveyor carriers laterally tilts only on a horizontal axis parallel to the direction of conveyor travel. While this accomplishes the objective of dumping the package from the carrier at the out-feed position, the package is often roughly tumbled or rolled, sometimes damaging the package and package""s contents. One reason for this is that the package typically is unloaded from the carrier while still traveling forward at the same speed as the conveyor. Thus, packages tend to slam into a forward retaining wall of the transition zone funnel or other package-receiving device.
Another problem with most conventional horizontally tilting conveyors is that because the package is moving forward at full speed when they are unloaded at the out-feed position, the transition zone funnel must be relatively wide so that the package does not miss the funnel and fall off the conveyor past the funnel. This often unnecessarily decreases the number and location of the out-feed positions of the conveyor system.
U.S. Pat. Nos. 4,744,454 and 5,086,905, both to Pxc3x6lling, disclose previous attempts to remedy this problem of rough handling by conventional laterally tilting conveyor carriers. Both of these patents to Polling disclose a conveyor element for a package conveyor that includes a tilting carrier tray mounted to be rotatable about two swivel axis. A first swivel shaft extends obliquely downward from the under side of the carrying tray and is in turn connected at an angle to the end of a second swivel shaft extending obliquely upwards from a base support part of the conveyor element. Together, the two swivel shafts form a xe2x80x9cVxe2x80x9d that points in the direction of the conveyor travel. Both of the swivel shafts lie in the vertical plain of symmetry of the conveyor element when the carrier tray is disposed in its upright position.
Because the carrier tray of Polling rotates about two oblique axis, the carrier tray tilts not only on a horizontal axis, but is moved through a geometrically complex spatial reorientation during package discharge. This allows for more gentle placement of a package on an out-feed chute than can be accomplished using conventional conveyor trays that laterally tip only on a horizontal axis because the Polling conveyor element imparts some degree of rearward velocity to the package as it is discharged, which, when added to the forward velocity of the conveyor system, results in the package""s forward velocity during discharge being lessened.
However, the conveyor elements of both of Pxc3x6lling""s patents are unduly complicated. In fact, the second Pxc3x6lling patent was directed towards simplifying the original design disclosed in the first Pxc3x6lling patent which was expensive and complicated to manufacture efficiently. As a result of this complexity and cost, the Pxc3x6lling devices have not enjoyed significant commercial acceptance and success. In addition, there is no provision in Pxc3x6lling to take advantage of the tilting movement of the tray to allow the direction of the discharged package to be further controlled.
Another significant disadvantages of conventionally designed package sorting conveyors is the lack of versatility and amount of floor space required by the conveyor, especially when sorting a variety of items on the same conveyor is desired. For example, it is common in distribution centers to sort items both contained in cardboard boxes, such as shoes, and in polyurethane bags, such as shirts.
Conventional sorting conveyors sort boxes and bags by providing package-receiving devices at out-feed positions that have a roller-lined surfaces for boxes, and more steeply declined package-receiving devices at different out-feed positions without rollers for bags. Thus a fixed number of box out-feed positions and bag out-feed positions are established on the conveyor. Alternatively, distribution centers may use two conventional sorting conveyors, one dedicated to boxes and one to bags.
It is often the case, however, that when sales product mixes change, a distribution center sorting both boxes and bags is required to sort either fewer boxes and more bags, or vice versa. In such cases, a distribution center using a sorting conveyor with a fixed number of out-feed positions for boxes and bags must make costly modifications to a conventionally designed sorting conveyor. In the alternative, the center may have designed excess out-feed positions for both boxes and bags into the conventional sorting conveyor in anticipation of product mix changes, which increases the size of the conventionally designed sorting conveyor. So the distribution center must choose between such competing alternatives.
Thus, there remains a need for a new and improved package sorting conveyor system having a conveying track and a transition zone funnel for receiving a package from the conveying track which is selectively positionable between at least a first and second position while, at the same time, includes a secondary chute downstream from the transition zone funnel having at least two definable discharge paths.
The present invention is directed to a package sorting conveyor system including: a conveying track; at least one unloading station; and a transition zone funnel upstream of the unloading station to receive the package from the conveying track, the transition zone funnel including a positioner assembly for selectively positioning the outlet of the transition zone funnel between at least a first and a second position. Also, in the preferred embodiment, the present invention includes a secondary downstream chute located downstream from the transition zone funnel for conveying the discharged package to its final destination.
In the preferred embodiment, the transition zone funnel includes: (i) an inlet adjacent to the conveying track at the unloading station for receiving the package; (ii) an upwardly inclined downstream wall located downstream of the inlet for preventing the package from tipping over; (iii) an outlet located downstream from the upwardly inclined downstream wall for discharging the package from the funnel; and (iv) a positioner assembly for selectively positioning the outlet of the transition zone funnel between at least a first and a second position along at least two axis.
Also, in the preferred embodiment, the inlet of the transition zone funnel is substantially flat to receive the package being discharged by the package sorting conveyor system. Also, the inlet may be wider than the front edge of the package providing a wider range of curvature enabling the package to slide off the package sorting conveyor system onto the inlet. The upwardly inclined downstream wall preferably has a radius of curvature of between about 6 inches and 2xc2xd feet, with about 1 foot being most preferred. Thus, the forward direction of the package may change about 90xc2x0 from its initial direction on the conveying track to its direction at the outlet of the funnel. In the preferred embodiment, the surface of the transition zone funnel is a low-friction, wear-resistant polymeric material, such as high-density polyethylene. The positioner assembly for selectively positioning between at least a first and a second position along at least two axis may further include at least one pivot point and a drive means. The pivot point may be a ball joint, an inclined axis or at least two independent pivots. In the preferred embodiment, the two independent pivots include a rotary joint and a hinge joint. The drive means for positioning may include a rotary actuator and a linear actuator. In the preferred embodiment, the linear actuator is a fluid actuator, such as a pneumatic air cylinder.
The transition zone funnel may further include a powered conveying section for accelerating or decelerating the package. The powered conveying section may be a powered roller or a powered belt.
The secondary chute may further include at least two definable discharge paths. In the preferred embodiment, at least one of the discharge path includes at least one path having a curved surface. In the preferred embodiment, the curved surface is between about 90xc2x0 and 360xc2x0. Also, in the preferred embodiment, the curved surface is between about 6 inches and 30 inches radius of curvature. The surface of the secondary downstream chute may be a low friction, wear resistant polymeric material. In the preferred embodiment, the material is a high density polyethylene.
Accordingly, one aspect of the present invention is to provide a package sorting conveyor system including: a conveying track; at least one unloading station; and a transition zone funnel upstream of the unloading station to receive the package, the transition zone funnel including a positioner assembly for selectively positioning the outlet of the transition zone funnel between at least a first and a second position.
Another aspect of the present invention is to provide a transition zone funnel for receiving a package discharged at an unloading station by a package sorting conveyor system having a conveying track, the transition zone funnel including: an inlet adjacent to the conveying track at the unloading station for receiving the package; an upwardly inclined downstream wall located downstream of the inlet for preventing the package from tipping over; an outlet located downstream from the upwardly inclined downstream wall for discharging the package from the funnel; and a positioner assembly for selectively positioning the outlet of the transition zone funnel between at least a first and a second position along at least two axis.
Still another aspect of the present invention is to provide a package sorting conveyor system including: a conveying track; at least one unloading station; a transition zone funnel upstream of the unloading station to receive the package from the conveying track, the transition zone funnel including: (i) an inlet adjacent to the conveying track at the unloading station for receiving the package; (ii) an upwardly inclined downstream wall located downstream of the inlet for preventing the package from tipping over; (iii) an outlet located downstream from the upwardly inclined downstream wall for discharging the package from the funnel; and (iv) a positioner assembly for selectively positioning the outlet of the transition zone funnel between at least a first and a second position along at least two axis; and a secondary downstream chute located downstream from the transition zone funnel for conveying the discharged package to its final destination.